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Elite on the BBC Micro

Equipment: EQSHP [Elite-A, Docked]

Name: EQSHP [Show more] Type: Subroutine Category: Equipment Summary: Show the Equip Ship screen (red key f3) or Buy Ship screen (CTRL-f3)
Context: See this subroutine in context in the source code References: This subroutine is called as follows: * TT102 calls EQSHP * eq calls entry point err

Other entry points: err Beep, pause and go to the docking bay (i.e. show the Status Mode screen) pres Given an item number A with the item name in recursive token Y, show an error to say that the item is already present, refund the cost of the item, and then beep and exit to the docking bay (i.e. show the Status Mode screen) pres+3 Show the error to say that an item is already present, and process a refund, but do not free up a space in the hold
\ --- Mod: Original Acornsoft code removed: -----------> \.bay \ JMP BAY \ Go to the docking bay (i.e. show the Status Mode \ \ screen) \ --- End of removed code -----------------------------> .EQSHP LDA #32 \ Clear the top part of the screen, draw a white border, JSR TT66 \ and set the current view type in QQ11 to 32 (Equip \ Ship screen) JSR FLKB \ Flush the keyboard buffer LDA #12 \ Move the text cursor to column 12 STA XC LDA #207 \ Print recursive token 47 ("EQUIP") followed by a space JSR spc LDA #185 \ Print recursive token 25 ("SHIP") and draw a JSR NLIN3 \ horizontal line at pixel row 19 to box in the title \ --- Mod: Original Acornsoft code removed: -----------> \ LDA #%10000000 \ Set bit 7 of QQ17 to switch to Sentence Case, with the \ STA QQ17 \ next letter in capitals \ --- And replaced by: --------------------------------> JSR vdu_80 \ Call vdu_80 to switch to Sentence Case, with the next \ letter in capitals \ --- End of replacement ------------------------------> INC YC \ Move the text cursor down one line \ --- Mod: Original Acornsoft code removed: -----------> \ LDA tek \ Fetch the tech level of the current system from tek \ CLC \ and add 3 (the tech level is stored as 0-14, so A is \ ADC #3 \ now set to between 3 and 17) \ CMP #12 \ If A >= 12 then set A = 14, so A is now set to between \ BCC P%+4 \ 3 and 14 \ LDA #14 \ STA Q \ Set QQ25 = A (so QQ25 is in the range 3-14 and \ STA QQ25 \ represents number of the most advanced item available \ INC Q \ in this system, which we can pass to gnum below when \ \ asking which item we want to buy) \ \ \ \ Set Q = A + 1 (so Q is in the range 4-15 and contains \ \ QQ25 + 1, i.e. the highest item number on sale + 1) \ LDA #70 \ Set A = 70 - QQ14, where QQ14 contains the current \ SEC \ fuel in light years * 10, so this leaves the amount \ SBC QQ14 \ of fuel we need to fill 'er up (in light years * 10) \ --- And replaced by: --------------------------------> JSR CTRL \ Scan the keyboard to see if CTRL is currently pressed, \ returning a negative value in A if it is BPL n_eqship \ If CTRL is not being pressed, jump down to n_eqship to \ keep processing the Equip Ship screen JMP n_buyship \ CTRL is being pressed, which means CTRL-f3 is being \ pressed, so jump to n_buyship to show the Buy Ship \ screen instead .bay JMP BAY \ Go to the docking bay (i.e. show the Status Mode \ screen) .n_eqship LDA tek \ Fetch the tech level of the current system from tek CLC \ and add 2 (the tech level is stored as 0-14, so A is ADC #2 \ now set to between 2 and 16) CMP #12 \ If A >= 12 then set A = 14, so A is now set to between BCC P%+4 \ 2 and 14 LDA #14 STA Q \ Set QQ25 = A (so QQ25 is in the range 2-14 and STA QQ25 \ represents number of the most advanced item available INC Q \ in this system, which we can pass to gnum below when \ asking which item we want to buy) \ \ Set Q = A + 1 (so Q is in the range 3-15 and contains \ QQ25 + 1, i.e. the highest item number on sale + 1) LDA new_range \ Set A = new_range - QQ14, where QQ14 contains the SEC \ current fuel in light years * 10, so this leaves the SBC QQ14 \ amount of fuel we need to fill 'er up (in light years \ * 10) \ --- End of replacement ------------------------------> ASL A \ The price of fuel is always 2 Cr per light year, so we STA PRXS \ double A and store it in PRXS, as the first price in \ the price list (which is reserved for fuel), and \ because the table contains prices as price * 10, it's \ in the right format (so tank containing 7.0 light \ years of fuel would be 14.0 Cr, or a PRXS value of \ 140) \ --- Mod: Code added for Elite-A: --------------------> LDA #0 \ As the maximum amount of fuel in Elite-A can be more ROL A \ than 25.5 light years, we need to use PRXS(1 0) to STA PRXS+1 \ store the fuel level, so this catches bit 7 from the \ left shift of the low byte above (which the ASL will \ have put into the C flag), and sets bit 0 of the high \ byte in PRXS+1 accordingly \ --- End of added code -------------------------------> LDX #1 \ We are now going to work our way through the equipment \ price list at PRXS, printing out the equipment that is \ available at this station, so set a counter in X, \ starting at 1, to hold the number of the current item \ plus 1 (so the item number in X loops through 1-13) .EQL1 STX XX13 \ Store the current item number + 1 in XX13 JSR TT67 \ Print a newline LDX XX13 \ Print the current item number + 1 to 3 digits, left- CLC \ padding with spaces, and with no decimal point, so the JSR pr2 \ items are numbered from 1 JSR TT162 \ Print a space LDA XX13 \ Print recursive token 104 + XX13, which will be in the CLC \ range 105 ("FUEL") to 116 ("GALACTIC HYPERSPACE ") ADC #104 \ so this prints the current item's name JSR TT27 LDA XX13 \ Call prx-3 to set (Y X) to the price of the item with JSR prx-3 \ number XX13 - 1 (as XX13 contains the item number + 1) SEC \ Set the C flag so we will print a decimal point when \ we print the price LDA #25 \ Move the text cursor to column 25 STA XC LDA #6 \ Print the number in (Y X) to 6 digits, left-padding JSR TT11 \ with spaces and including a decimal point, which will \ be the correct price for this item as (Y X) contains \ the price * 10, so the trailing zero will go after the \ decimal point (i.e. 5250 will be printed as 525.0) LDX XX13 \ Increment the current item number in XX13 INX CPX Q \ If X < Q, loop back up to print the next item on the BCC EQL1 \ list of equipment available at this station JSR CLYNS \ Clear the bottom three text rows of the upper screen, \ and move the text cursor to column 1 on row 21, i.e. \ the start of the top row of the three bottom rows LDA #127 \ Print recursive token 127 ("ITEM") followed by a JSR prq \ question mark JSR gnum \ Call gnum to get a number from the keyboard, which \ will be the number of the item we want to purchase, \ returning the number entered in A and R, and setting \ the C flag if the number is bigger than the highest \ item number in QQ25 BEQ bay \ If no number was entered, jump up to bay to go to the \ docking bay (i.e. show the Status Mode screen) BCS bay \ If the number entered was too big, jump up to bay to \ go to the docking bay (i.e. show the Status Mode \ screen) SBC #0 \ Set A to the number entered - 1 (because the C flag is \ clear), which will be the actual item number we want \ to buy LDX #2 \ Move the text cursor to column 2 STX XC INC YC \ Move the text cursor down one line \ --- Mod: Original Acornsoft code removed: -----------> \ PHA \ While preserving the value in A, call eq to subtract \ JSR eq \ the price of the item we want to buy (which is in A) \ PLA \ from our cash pot, but only if we have enough cash in \ \ the pot. If we don't have enough cash, exit to the \ \ docking bay (i.e. show the Status Mode screen) \ --- And replaced by: --------------------------------> PHA \ Store A on the stack so we can restore it after the \ following code CMP #2 \ If A < 2, then we are buying fuel or missiles, so jump BCC equip_space \ down to equip_space to skip the checks for whether we \ have enough free space in the hold (as fuel and \ missiles don't take up hold space) LDA QQ20+16 \ Fetch the number of alien items in the hold into A, so \ the following call to Tml will include these in the \ total SEC \ Call Tml with X = 12 and the C flag set, to work out LDX #12 \ if there is space for one more tonne in the hold JSR Tml BCC equip_isspace \ If the C flag is clear then there is indeed room for \ another tonne, so jump to equip_isspace so we can buy \ the new piece of equipment LDA #14 \ Otherwise there isn't room in the hold for any more \ equipment, so set set A to the value for recursive \ token 14 ("UNIT") JMP query_beep \ Print the recursive token given in A followed by a \ question mark, then make a beep, pause and go to the \ docking bay (i.e. show the Status Mode screen) .equip_isspace DEC new_hold \ We are now going to buy the piece of equipment, so \ decrement the free space in the hold, as equipment \ takes up hold space in Elite-A PLA \ Set A to the value from the top of the stack (so it PHA \ contains the number of the item we want to buy) .equip_space JSR eq \ Call eq to subtract the price of the item we want to \ buy (which is in A) from our cash pot, but only if we \ have enough cash in the pot. If we don't have enough \ cash, exit to the docking bay (i.e. show the Status \ Mode screen) PLA \ Restore A from the stack \ --- End of replacement ------------------------------> BNE et0 \ If A is not 0 (i.e. the item we've just bought is not \ fuel), skip to et0 \ --- Mod: Original Acornsoft code removed: -----------> \ LDX #70 \ Set the current fuel level * 10 in QQ14 to 70, or 7.0 \ STX QQ14 \ light years (a full tank) \ --- And replaced by: --------------------------------> LDX new_range \ Set the current fuel level in QQ14 to our current STX QQ14 \ ship's maximum hyperspace range from new_range, so the \ tank is now full JSR DIALS \ Call DIALS to update the dashboard with the new fuel \ level LDA #0 \ Set A to 0 as the call to DIALS will have overwritten \ the original value, and we still need it set \ correctly so we can continue through the conditional \ statements for all the other equipment \ --- End of replacement ------------------------------> .et0 CMP #1 \ If A is not 1 (i.e. the item we've just bought is not BNE et1 \ a missile), skip to et1 LDX NOMSL \ Fetch the current number of missiles from NOMSL into X INX \ Increment X to the new number of missiles LDY #124 \ Set Y to recursive token 124 ("ALL") \ --- Mod: Original Acornsoft code removed: -----------> \ CPX #5 \ If buying this missile would give us 5 missiles, this \ BCS pres \ is more than the maximum of 4 missiles that we can \ \ fit, so jump to pres to show the error "All Present", \ \ beep and exit to the docking bay (i.e. show the Status \ \ Mode screen) \ --- And replaced by: --------------------------------> CPX new_missiles \ If buying this missile would give us more than the BCS pres+3 \ maximum number of missiles that our current ship can \ hold (which is stored in new_missiles), jump to pres+3 \ to show the error "All Present", do not free up any \ space in the hold (as missiles do not take up hold \ space), beep and exit to the docking bay (i.e. show \ the Status Mode screen) \ --- End of replacement ------------------------------> STX NOMSL \ Otherwise update the number of missiles in NOMSL JSR msblob \ Reset the dashboard's missile indicators so none of \ them are targeted .et1 \ --- Mod: Original Acornsoft code removed: -----------> \ LDY #107 \ Set Y to recursive token 107 ("LARGE CARGO{sentence \ \ case} BAY") \ CMP #2 \ If A is not 2 (i.e. the item we've just bought is not \ BNE et2 \ a large cargo bay), skip to et2 \ LDX #37 \ If our current cargo capacity in CRGO is 37, then we \ CPX CRGO \ already have a large cargo bay fitted, so jump to pres \ BEQ pres \ to show the error "Large Cargo Bay Present", beep and \ \ exit to the docking bay (i.e. show the Status Mode \ \ screen) \ STX CRGO \ Otherwise we just scored ourselves a large cargo bay, \ \ so update our current cargo capacity in CRGO to 37 \ --- And replaced by: --------------------------------> LDY #107 \ Set Y to recursive token 107 ("I.F.F.SYSTEM") CMP #2 \ If A is not 2 (i.e. the item we've just bought is not BNE et2 \ an I.F.F. system), skip to et2 LDX CRGO \ If we already have an I.F.F. system fitted (i.e. CRGO BNE pres \ is non-zero), jump to pres to show the error "I.F.F. \ System Present", beep and exit to the docking bay \ (i.e. show the Status Mode screen) DEC CRGO \ Otherwise we just scored ourselves an I.F.F. system, \ so set CRGO to &FF (as CRGO was 0 before the DEC \ instruction) \ --- End of replacement ------------------------------> .et2 CMP #3 \ If A is not 3 (i.e. the item we've just bought is not BNE et3 \ an E.C.M. system), skip to et3 INY \ Increment Y to recursive token 108 ("E.C.M.SYSTEM") LDX ECM \ If we already have an E.C.M. fitted (i.e. ECM is BNE pres \ non-zero), jump to pres to show the error "E.C.M. \ System Present", beep and exit to the docking bay \ (i.e. show the Status Mode screen) DEC ECM \ Otherwise we just took delivery of a brand new E.C.M. \ system, so set ECM to &FF (as ECM was 0 before the DEC \ instruction) .et3 CMP #4 \ If A is not 4 (i.e. the item we've just bought is not BNE et4 \ an extra pulse laser), skip to et4 \ --- Mod: Original Acornsoft code removed: -----------> \ JSR qv \ Print a menu listing the four views, with a "View ?" \ \ prompt, and ask for a view number, which is returned \ \ in X (which now contains 0-3) \ LDA #POW \ Call refund with A set to the power of the new pulse \ JSR refund \ laser to install the new laser and process a refund if \ \ we already have a laser fitted to this view \ LDA #4 \ Set A to 4 as we just overwrote the original value, \ \ and we still need it set correctly so we can continue \ \ through the conditional statements for all the other \ \ equipment \ --- And replaced by: --------------------------------> LDY new_pulse \ Set Y to the power level of pulse lasers when fitted \ to our current ship type BNE equip_leap \ Jump to equip_merge (via equip_leap) to install the \ new laser (this BNE is effectively a JMP as Y is never \ zero) \ --- End of replacement ------------------------------> .et4 CMP #5 \ If A is not 5 (i.e. the item we've just bought is not BNE et5 \ an extra beam laser), skip to et5 \ --- Mod: Original Acornsoft code removed: -----------> \ JSR qv \ Print a menu listing the four views, with a "View ?" \ \ prompt, and ask for a view number, which is returned \ \ in X (which now contains 0-3) \ LDA #POW+128 \ Call refund with A set to the power of the new beam \ JSR refund \ laser to install the new laser and process a refund if \ \ we already have a laser fitted to this view \ --- And replaced by: --------------------------------> LDY new_beam \ Set Y to the power level of beam lasers when fitted to \ our current ship type .equip_leap BNE equip_frog \ Jump to equip_merge (via equip_frog) to install the \ new laser (this BNE is effectively a JMP as Y is never \ zero) \ --- End of replacement ------------------------------> .et5 LDY #111 \ Set Y to recursive token 107 ("FUEL SCOOPS") CMP #6 \ If A is not 6 (i.e. the item we've just bought is not BNE et6 \ a fuel scoop), skip to et6 LDX BST \ If we already have fuel scoops fitted (i.e. BST is BEQ ed9 \ zero), jump to ed9, otherwise fall through into pres \ to show the error "Fuel Scoops Present", beep and \ exit to the docking bay (i.e. show the Status Mode \ screen) .pres \ If we get here we need to show an error to say that \ the item whose name is in recursive token Y is already \ present, and then process a refund for the cost of \ item number A \ --- Mod: Code added for Elite-A: --------------------> INC new_hold \ We can't buy the requested equipment, so increment the \ free space in the hold, as we decremented it earler \ in anticipation of making a deal, but the deal has \ fallen through \ --- End of added code -------------------------------> STY K \ Store the item's name in K JSR prx \ Call prx to set (Y X) to the price of equipment item \ number A JSR MCASH \ Add (Y X) cash to the cash pot in CASH, as the station \ already took the money for this item in the JSR eq \ instruction above, but we can't fit the item, so need \ our money back LDA K \ Print the recursive token in K (the item's name) JSR spc \ followed by a space LDA #31 \ Print recursive token 145 ("PRESENT") JSR TT27 .err JSR dn2 \ Call dn2 to make a short, high beep and delay for 1 \ second JMP BAY \ Jump to BAY to go to the docking bay (i.e. show the \ Status Mode screen) .ed9 DEC BST \ We just bought a shiny new fuel scoop, so set BST to \ &FF (as BST was 0 before the jump to ed9 above) .et6 INY \ Increment Y to recursive token 112 ("E.C.M.SYSTEM") CMP #7 \ If A is not 7 (i.e. the item we've just bought is not BNE et7 \ an escape pod), skip to et7 LDX ESCP \ If we already have an escape pod fitted (i.e. ESCP is BNE pres \ non-zero), jump to pres to show the error "Escape Pod \ Present", beep and exit to the docking bay (i.e. show \ the Status Mode screen) DEC ESCP \ Otherwise we just bought an escape pod, so set ESCP \ to &FF (as ESCP was 0 before the DEC instruction) .et7 \ --- Mod: Original Acornsoft code removed: -----------> \ INY \ Increment Y to recursive token 113 ("ENERGY BOMB") \ CMP #8 \ If A is not 8 (i.e. the item we've just bought is not \ BNE et8 \ an energy bomb), skip to et8 \ LDX BOMB \ If we already have an energy bomb fitted (i.e. BOMB \ BNE pres \ is non-zero), jump to pres to show the error "Energy \ \ Bomb Present", beep and exit to the docking bay (i.e. \ \ show the Status Mode screen) \ LDX #&7F \ Otherwise we just bought an energy bomb, so set BOMB \ STX BOMB \ to &7F \ --- And replaced by: --------------------------------> INY \ Increment Y to recursive token 113 ("HYPERSPACE UNIT") CMP #8 \ If A is not 8 (i.e. the item we've just bought is not BNE et8 \ a hyperspace unit), skip to et8 LDX BOMB \ If we already have a hyperspace unit fitted (i.e. BOMB BNE pres \ is non-zero), jump to pres to show the error \ "Hyperspace Unit Present", beep and exit to the \ docking bay (i.e. show the Status Mode screen) DEC BOMB \ Otherwise we just bought an energy bomb, so set BOMB \ to &FF (as BOMB was 0 before the DEC instruction) \ --- End of replacement ------------------------------> .et8 INY \ Increment Y to recursive token 114 ("ENERGY UNIT") CMP #9 \ If A is not 9 (i.e. the item we've just bought is not BNE etA \ an energy unit), skip to etA LDX ENGY \ If we already have an energy unit fitted (i.e. ENGY is BNE pres \ non-zero), jump to pres to show the error "Energy Unit \ Present", beep and exit to the docking bay (i.e. show \ the Status Mode screen) \ --- Mod: Original Acornsoft code removed: -----------> \ INC ENGY \ Otherwise we just picked up an energy unit, so set \ \ ENGY to 1 (as ENGY was 0 before the INC instruction) \ --- And replaced by: --------------------------------> LDX new_energy \ Otherwise we just picked up an energy unit, so set STX ENGY \ ENGY to new_energy, which is the value of our current \ ship's ship energy refresh rate with an energy unit \ fitted \ --- End of replacement ------------------------------> .etA INY \ Increment Y to recursive token 115 ("DOCKING \ COMPUTERS") CMP #10 \ If A is not 10 (i.e. the item we've just bought is not BNE etB \ a docking computer), skip to etB LDX DKCMP \ If we already have a docking computer fitted (i.e. BNE pres \ DKCMP is non-zero), jump to pres to show the error \ "Docking Computer Present", beep and exit to the \ docking bay (i.e. show the Status Mode screen) DEC DKCMP \ Otherwise we just got hold of a docking computer, so \ set DKCMP to &FF (as DKCMP was 0 before the DEC \ instruction) .etB INY \ Increment Y to recursive token 116 ("GALACTIC \ HYPERSPACE ") CMP #11 \ If A is not 11 (i.e. the item we've just bought is not BNE et9 \ a galactic hyperdrive), skip to et9 \ --- Mod: Original Acornsoft code removed: -----------> \ LDX GHYP \ If we already have a galactic hyperdrive fitted (i.e. \ BNE pres \ GHYP is non-zero), jump to pres to show the error \ \ "Galactic Hyperspace Present", beep and exit to the \ \ docking bay (i.e. show the Status Mode screen) \ --- And replaced by: --------------------------------> LDX GHYP \ Set X to the value of GHYP, which determines \ whether we have a galactic hyperdrive fitted .equip_gfrog BNE pres \ If we already have a galactic hyperdrive fitted (i.e. \ GHYP is non-zero), jump to pres to show the error \ "Galactic Hyperspace Present", beep and exit to the \ docking bay (i.e. show the Status Mode screen) \ --- End of replacement ------------------------------> DEC GHYP \ Otherwise we just splashed out on a galactic \ hyperdrive, so set GHYP to &FF (as GHYP was 0 before \ the DEC instruction) .et9 INY \ Increment Y to recursive token 117 ("MILITARY LASER") CMP #12 \ If A is not 12 (i.e. the item we've just bought is not BNE et10 \ a military laser), skip to et10 \ --- Mod: Original Acornsoft code removed: -----------> \ JSR qv \ Print a menu listing the four views, with a "View ?" \ \ prompt, and ask for a view number, which is returned \ \ in X (which now contains 0-3) \ LDA #Armlas \ Call refund with A set to the power of the new \ JSR refund \ military laser to install the new laser and process a \ \ refund if we already have a laser fitted to this view \.et10 \ INY \ Increment Y to recursive token 118 ("MINING LASER") \ CMP #13 \ If A is not 13 (i.e. the item we've just bought is not \ BNE et11 \ a mining laser), skip to et11 \ JSR qv \ Print a menu listing the four views, with a "View ?" \ \ prompt, and ask for a view number, which is returned \ \ in X (which now contains 0-3) \ LDA #Mlas \ Call refund with A set to the power of the new mining \ JSR refund \ laser to install the new laser and process a refund if \ \ we already have a laser fitted to this view \ --- And replaced by: --------------------------------> LDY new_military \ Set Y to the power level of military lasers when \ fitted to our current ship type .equip_frog BNE equip_merge \ Jump to equip_merge to install the new laser (this BNE \ is effectively a JMP as Y is never zero) .et10 INY \ Increment Y to recursive token 118 ("MINING LASER") CMP #13 \ If A is not 13 (i.e. the item we've just bought is not BNE et11 \ a mining laser), skip to et11 LDY new_mining \ Set Y to the power level of mining lasers when fitted \ to our current ship type .equip_merge \ Now to install a new laser with the laser power in Y \ and the item number in A PHA \ Store the item number in A on the stack TYA \ Store the laser power in Y on the stack PHA JSR qv \ Print a menu listing the four views, with a "View ?" \ prompt, and ask for a view number, which is returned \ in X (which now contains 0-3) PLA \ Retrieve the laser power of the new laser from the \ stack into A LDY LASER,X \ If there is no laser mounted in the chosen view (i.e. BEQ l_3113 \ LASER+X, which contains the laser power for view X, is \ zero), jump to l_3113 to fit the new laser \ We already have a laser fitted to this view, so PLA \ Retrieve the item number from the stack into A LDY #187 \ Set Y to token 27 (" LASER") so the following jump to \ pres will show the error "Laser Present", beep and \ exit to the docking bay (i.e. show the Status Mode \ screen) BNE equip_gfrog \ Jump to pres via equip_gfrog (this BNE is effectively \ a JMP as Y is never zero) .l_3113 STA LASER,X \ Fit the new laser by storing the laser power in A into \ LASER+X PLA \ Retrieve the item number from the stack into A \ --- End of replacement ------------------------------> .et11 JSR dn \ We are done buying equipment, so print the amount of \ cash left in the cash pot, then make a short, high \ beep to confirm the purchase, and delay for 1 second JMP EQSHP \ Jump back up to EQSHP to show the Equip Ship screen \ again and see if we can't track down another bargain